Cellular mobile communication technology is technology for providing communication service to a wireless device using infrastructure such as a base station wireless device. However, demands for technology, which is about using the communication service without infrastructure such as a base station by means of recognizing wireless devices with one another and directly transmitting data between wireless devices with one another, are increasing. In the case of the communication service without the infrastructure, in order to transmit data from each wireless device to other wireless devices, the data may go through other wireless devices.
When using this technique, multicast service, which generates a multicasting group by grouping wireless devices having the same concern, and transmit data to wireless devices contained in the multicasting group, is needed.
In the case of the communication service with infra such as cellular mobile communication, the multicast data is directly transmitted from the infra such as a base station to a wireless device. Accordingly, data transmission is relatively simple and, reliable multicast service is easy.
However, in the case of the communication service without the infra, in order to transmit the multicast data from a source wireless device to a target wireless device, the data may go through a plurality of wireless devices. In this case, it may be difficult to provide reliable multicast service.